Results 1 to 8 of 8

Thread: dresser backs and case rigidity

  1. #1
    Join Date
    Jul 2010
    Location
    Brooklyn, NY
    Posts
    155

    dresser backs and case rigidity

    Good morning,

    A lot of you have helped me out with a post I recently placed entitled "Are 23" Miters possible." Thank you. I think I've decided on going with the full blind, or secret, dovetail. I'm a little nervous about attempting such a complicated joint, but I think with practice, I might be able to pull it off. My next question is a basic wood movement/case construction question. Actually, there's two parts to this question:

    1. I believe that "panel" construction is the term that describes my face frame-less type construction??? I'll also be using Blum drawer slides. So, I will have no skeleton or webbing(is this the proper term?) within the case, and no face frame to help with the overall rigidity of the box. I've never built a case before and am wondering if there will be enough rigidity to the whole thing with only the 4 mitered joints connecting the top, sides, and bottom. Is there something I need to work into the design to stiffen the case up?

    Which brings me to the second part of the question...

    2. Is there a way to construct the back to help with the above problem? It, too, will be made from solid wood. Because I have to avoid cross grain movement(is this the proper term?) I'm imaging I'll have to float the back in dadoes running along the inside of the sides, top, and bottom, to allow for seasonal movement. Is this the way to go? What other methods are there for affixing a solid wood back to a case like this? And if I do float the back in dadoes, would I want to pin it in a single place in the center of the panel? And if I do pin it in the center, will this provide sufficient rigidity on its own?

    Thanks to everyone for helping me through this learning process. I very much appreciate all of the knowledge that so many here at Sawmillcreek freely impart.

    David

  2. #2
    Join Date
    Feb 2010
    Location
    Philadelphia, PA
    Posts
    3,644
    You could make the back using frame and panel construction (like frame and panel door). Then you will have a single solid structure, with a panel that can expand and contract in the center.
    Woodworking is terrific for keeping in shape, but it's also a deadly serious killing system...

  3. #3
    Join Date
    Mar 2009
    Location
    Chevy Chase, Maryland
    Posts
    2,080
    Is the back going to show? If not, use high quality plywood. It will add significant strength against any racking forces.

    I'm not sure I understand your wood movement concerns. The carcase should only breathe in depth, right? If you are talking about using solid wood for the back and its movement, it will only need to move width. The typical way to deal this would be to use tongue and groove or ship lapped boards - screwed only at the center of each board - in a rabbetted carcase back.

  4. #4
    How many drawers? I wouldn't want something this large to rack...

    I would think something should be used to brace the works,
    either between the drawers, or in the corners.

  5. #5
    Join Date
    Jul 2010
    Location
    Brooklyn, NY
    Posts
    155
    The frame and panel idea is a good one, but it would mean I'd see the edge of the frame board on the top of the dresser -- something I'm trying to avoid. The back will be about 26" high by about 36" wide. I was planning on gluing up a panel of this size and letting it float in dadoes. Is this not something you would do?

    Regarding wood movement... The carcase will only breath in depth, but the back will move in width. And because the panel will be 36" wide, it will likely move a significant enough amount to cause problems. I guess that by pinning it to the top and bottom in the center some stiffness against racking would be achieved. And maybe I could run some sort of internal rail or runner horizontally from one side to the other. In the space behind the drawers.

    What do you think?

  6. #6
    Join Date
    Feb 2010
    Location
    Philadelphia, PA
    Posts
    3,644
    RE: the frame and panel. You would set in in rabbets on the back so it would not show from the sides or top. You would use some type of fastener to hold it in the rabbets. I suppose you could also rabbet a tongue of some kind onto the rails and styles and then set them into grooves.

    Actually I would think that a classic tongue and groove or ship lapped back would also do a lot to support the carcass since the boards on the far edges of the case typically have fasteners run up the height and than at least one on each end attaching each board to the top and bottom.

    Your idea of just let just setting the panel in grooves may work just fine, but its large enough that you'll need to leave a good amount of space for movement (relatively) and at that point I'm not sure how its supporting the carcass.

    The more I think about it the more I think you should rabbet the back and either very solidly fasten a high quality tight fitting piece of plywood in there or solidly fasten a classic tongue and groove back in there.
    Woodworking is terrific for keeping in shape, but it's also a deadly serious killing system...

  7. #7
    Since you designed it without cross members, it sounds like a piece of ply is really the strongest/easiest way to fix your problem. I know many people don't like using ply but given that it wont show in the back and is dimensionally stable it does have its uses. Set it into a rabbet and the ugly side grain wont show. Set the dresser against a wall and no one can see the ply at all. Ship lapped or T&G boards would work as well but don't offer quite as much torsional strength.

  8. #8
    Quote Originally Posted by David Wadstrup View Post
    Good morning,

    A lot of you have helped me out with a post I recently placed entitled "Are 23" Miters possible." Thank you. I think I've decided on going with the full blind, or secret, dovetail. I'm a little nervous about attempting such a complicated joint, but I think with practice, I might be able to pull it off. My next question is a basic wood movement/case construction question. Actually, there's two parts to this question:

    1. I believe that "panel" construction is the term that describes my face frame-less type construction??? I'll also be using Blum drawer slides. So, I will have no skeleton or webbing(is this the proper term?) within the case, and no face frame to help with the overall rigidity of the box. I've never built a case before and am wondering if there will be enough rigidity to the whole thing with only the 4 mitered joints connecting the top, sides, and bottom. Is there something I need to work into the design to stiffen the case up?

    Which brings me to the second part of the question...

    2. Is there a way to construct the back to help with the above problem? It, too, will be made from solid wood. Because I have to avoid cross grain movement(is this the proper term?) I'm imaging I'll have to float the back in dadoes running along the inside of the sides, top, and bottom, to allow for seasonal movement. Is this the way to go? What other methods are there for affixing a solid wood back to a case like this? And if I do float the back in dadoes, would I want to pin it in a single place in the center of the panel? And if I do pin it in the center, will this provide sufficient rigidity on its own?

    Thanks to everyone for helping me through this learning process. I very much appreciate all of the knowledge that so many here at Sawmillcreek freely impart.

    David
    I don't know what the consensus was from your other thread on long miters, but your case miter joints need to be reinforced with splines or dowels. With no face frame, dowels would be the totally invisible solution. You can make stopped spline joints but the whole affair would be a lot more difficult than using dowels.

    A frame and panel back, set in rebates, spot glued and screwed (countersunk very high quality brass screws, two to four per edge depending on size of the cabinet) would certainly be a nice choice. With frame and panel construction you don't have to worry about overall movement of the back, ditto plywood. The whole thing depends on whether the piece is designed to sit away from the wall, where the back will be visible.
    Last edited by Charlie Stanford; 02-05-2013 at 11:51 AM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •